US Appeals Court strikes down California marine auxiliary engine rule

28 February 2008

The US 9th Circuit Court of Appeals in San Francisco ruled that the California Air Resources Board (ARB) cannot force ocean ships to run their auxiliary diesel engines on low sulfur fuel when they are in California waters. The Court found that the California’s regulation is preempted by federal law.

This Appeals Court ruling upholds the August 2007 decision of a District Court, which found that the ARB regulation is preempted by the Clean Air Act (CAA), and it wrongly complicates international commerce.

The ARB rule, adopted in 2005 and effective from January 2007, prohibited marine diesel auxiliary engines, including diesel-electric engines, on ships operating within 24 miles of California coastline to emit pollutants at levels that would exceed those from burning 0.5% sulfur marine diesel or gasoil fuel. The rule was challenged by the Pacific Merchant Shipping Association (PMSA) on grounds that the 1990 Clean Air Act Amendments require California to receive authorization from the US Environmental Protection Agency (EPA) for controls over off-road sources such as marine engines. The ARB argued that its rule was not preempted by the CAA because it only imposed “in-use operational requirements” on existing engines, as opposed to new engine controls covered by the CAA.

Under the court ruling, the ARB must seek an EPA waiver for its marine engine regulation(s). It is not clear if the EPA is likely to approve such waiver for the marine rule. Control of air pollution from ships, airplanes and railroads by states has been controversial due to potential conflicts with laws safeguarding interstate commerce. Concerns also exist that marine and aviation rules should be international.

In December 2007, the EPA denied an ARB waiver request to impose regulation for greenhouse gas emissions from motor vehicles. The EPA argued that climate change is a global problem, which should be addressed by federal legislation rather than by states.

The ARB was also developing another rule, which would require ships to switch to low-sulfur fuels in their main engines when within 24 miles from California coasts.